1. Field of the Invention
The present invention relates to a changing device for the screw cylinder or extruder barrel of an injection molding machine. The screw of the screw cylinder is in releasable coupling connection with the drive unit of the machine. For releasing and uncoupling the coupling connection, the screw cylinder including screw can be displaced relative to the injection molding machine essentially transversely of the longitudinal direction of the screw cylinder. Two hydraulic cylinders are arranged spaced apart next to each other symmetrically and parallel to the longitudinal center plane of the injection molding machine. The two cylinders are connected to each other by means of a transverse member. A free space extending forwardly from the drive unit is defined by the two hydraulic cylinders and the transverse member. This free space forms an alignment seat which is open toward the front and the back and a longitudinal side. In the coupled position, the screw cylinder is fixable and/or lockable to the drive unit in this alignment seat.
2. Description of the Prior Art
In injection molding machines for processing thermoplastic materials, it is relatively frequently necessary to exchange the screw cylinder, particularly when the plastics material to be processed is changed and when the coloring agent is changed. The screw cylinder is usually disconnected for this purpose from the material feeding units of the injection molding machine and from the drive unit for the screw which drive unit is part of the machine. Subsequently, the screw cylinder is removed from the injection molding machine by using a lifting unit.
The operating steps and/or manipulations required for changing the screw cylinder are quite complicated and, therefore, require that the respective injection molding machine stands still for a relatively long time which leads to a loss of production.
It is, therefore, the primary object of the present invention to provide a changing device for the screw cylinder of an injection molding machine in which the assembly and disassembly operations to be carried out are substantially simplified and, thus, the periods of standstill of the injection molding machine are reduced.